Understanding Speed, Velocity, and Acceleration
Speed is simply how fast you are going, with no regard to direction. Velocity, however, must also have the direction specified. Both are measured in m/s, km/h, or mph.
- Average speed = Distance moved ÷ Time taken (s = v × t)
- Acceleration = Change in velocity ÷ Time taken ((v-u) = a × t, v² = u² + 2as)
Distance-Time Graphs
- Flat sections indicate the object is stopped.
- A steeper graph means the object is moving faster.
- Curves represent acceleration.
- A curve getting steeper means speeding up.
- A leveling-
Gravitational, Electric, and Magnetic Fields
Here’s a comparison of gravitational, electric, and magnetic fields:
Field Characteristics
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Gravitational Field:
- A field of forces acting on bodies with mass.
- The force exerted is proportional to the mass acted upon.
- The gravitational force is always attractive.
- The field is defined at each point by the vector field g = F / m.
- The gravitational field strength due to a point mass is inversely proportional to the square of the distance: g = G · m/r2.
- The universal gravitational constant (G) is the same in
Optical Amplifiers: EDFA, Raman, and SOA
EDFAs use a pump laser (980 nm or 1480 nm) to bring electrons up to a higher energy level. Signal amplification is achieved by emitted photons of the same signal wavelength with the help of stimulated emission.
EDFA Parameters
- Gain: Ratio of the input power to the output power (in dB)
- Bandwidth: Range of wavelengths in which amplification is obtained
- Gain Saturation: Point at which the output power ceases to grow with respect to the increase in input power
- Noise Figure: Ratio of the SNR at the input
Energy and Heat: Key Concepts and Conversions
Questions
Describe how energy can be converted from one form to another in a wind-up toy. Elastic potential energy stored in the wound-up spring is converted to kinetic energy as the spring unwinds and the toy moves.
What is the law of conservation of energy state? Energy cannot be created or destroyed.
As an object falls in free fall, what energy change is taking place? Gravitational potential energy is converted into kinetic energy as the object falls.
What did Einstein conclude about the relationship
British Slang and Phrases: Meanings
This is a list of British slang words and phrases with their meanings:
- A tidy packet: A lot of money.
- Aerial: A piece of equipment made of wire or long, straight pieces of metal for receiving or sending radio and television signals.
- At an angle: Diagonally.
- Breeches: Short trousers/pants fastened just below the knee.
- Buckle: A piece of metal at the end of a belt which is used to fasten it.
- Buttercup: A wild plant with small, shiny, yellow flowers that are shaped like cups.
- Carbon copy: A copy of a document,
Pre-Socratic Philosophers: Monists and Pluralists
Pre-Socratic Philosophers
Monists
Thales of Miletus
Thales, the founder of this philosophy, proposed water as the fundamental principle (arche). He believed the Earth rested on water and that inanimate objects possessed souls, based on observations of magnets and amber. He also posited that water was the principle of all elements and that the cosmos was animated and full of divine power.
Anaximander of Miletus
Anaximander, a companion of Thales, argued for a single, moving, and infinite principle called
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